SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93ee874711af51b21a72bca4072d25d239ecbffc98d612fdb968e3c6b7afd67c' 
  AND token = 'sXqNNuYHuYLcHhONS4Sfm4VIDQjBNG6wqFCs6ZxwSbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}